While researching this ‘new’ feature I found references to Exchange 2010 SP2 Rollup Update 4. So I decided to see if the feature had been added earlier. First we can start with the Description of RU4 to see what fixes are included. If you read the list you see a reference to an issue with how Sent Items are handled:
If we then go to the TechNet article we see that there was a ‘fix’ for the inherent behavior in Exchange. In fact, two new PowerShell commands were added here as well:
Get-MailboxSentItemsConfiguration – http://technet.microsoft.com/en-us/library/jj884077(v=exchg.141).aspx
Set-MailboxSentItemsConfiguration – http://technet.microsoft.com/en-us/library/jj884078(v=exchg.141).aspx
Prior to this change any message that was sent On Behalf or using ‘Send As’ was stored in the senders Sent Items. With this change you are now able to specify where the sent message is stored. Apparently Microsoft did listen to their user base and decided to add this functionality.
I also verified that the changes were not just in the backend and were indeed visible to the end user as well: